The present invention relates to pharmaceutical compositions with antitumour activity, containing as active ingredient one or more acylcarnitines optionally in combination with other substances with antitumour activity. In particular, the invention relates to pharmaceutical compositions with antitumour activity, containing as active ingredient L-acetylcarnitine optionally in combination with somatostatin. The invention further relates to the use of acylcarnitines, in particular L-acetylcarnitine, for the preparation of medicaments with antitumour activity. Carnitines (which herein means carnitine, as well as the acylderivatives, optical isomers and racemates thereof) are compounds naturally occurring in various organs and systems of a number of living species, both vegetables and animals. Such compounds are available in the synthetic form, and they are used in common clinical practice in the treatment of primary carnitine deficiency, senile dementia and peripheral neuropathies. The recommended dosage for use in humans is about 30/mg/kg/day.
More particularly, acylcarnitines show a number of therapeutical properties, in that they have immunomodulating, antibacterial, antifungal, antishock, antidyslipidemic activities. Furthermore, they have a remarkable antiviral activity.
It has now been surprisingly found that acylcarnitines have a remarkable antitumour activity.
It has, for example, been observed that acetylcarnitine (N,N,N,-trimethyl-xcex2-acetoxy-butyrobetaine), of formula 
mainly in its L form, has a strong antitumour activity, both in animals and in humans and can therefore be used, either alone or in combination with other antitumour medicaments, in the treatment of malignant tumours.
Pre-treatment with acylcarnitine, in particular with L-acetylcarnitine, has been found to prevent the thriving of transplanted neoplasms in the animals and the relapses of resected neoplasms in humans.